編集可能なセレクトボックスを作る

<select style="width:120px; clip:rect(0px,120px,22px,100px); position:absolute;" onchange="select(this);">
    <option>test</option>
    <option>test1</option>
    <option>test2</option>
  </select>
  <input id="t1" type="text" style="width:100px;margin-right:20px;">
  bbb
  <script language="javascript">
    function select(obj){
      document.getElementById("t1").value=obj.options[obj.selectedIndex].text;
    }
  </script>